I'm going to be more toned down than some of the conservative commentators I've read. Yes, military recruitment centers have for a long time been subject to vicious attacks in the form of intimidation, vandalization, and violence. (Read Michelle Malkin's summary of the anti-military movement's destructive tendencies here.) But at the same time, it isn't the entire movement or even the majority of the anti-war movement. As conservatives, we cannot stoop to the orthodox liberal belief that society or an entire demographic group is really to blame when these things happen. One person or a small group of people did this. A very small proportion of Americans (although that term hardly seems warranted) will rejoice with them. But I suspect most regular anti-war folks don't agree with the tactic.
That is not to say that we should not be aware of where the anti-war movement comes from. Such movements are, at their core, centered around organizations; these organizations are almost universally socialist (like International ANSWER, a subsidiary of the Trotsky-ite World Workers' Party) or anarchist (such as, apparently, these Times Square bombers). It was only barely a secret that the anti-Vietnam War movement was heavily funded by the Soviet Union through various large organizations; the impetus behind today's anti-war movement is seemingly a much more well-kept secret.